Transfer type coating mechanism and transfer type coating equipment

Abstract

The utility model discloses a transfer type coating mechanism and transfer type coating equipment, the transfer type coating mechanism comprises a coating roller, one side of the coating roller is provided with a slurry tank, in the autorotation process of the coating roller, slurry in the slurry tank is coated on the surface of the coating roller, and a coating area is formed on the surface of the coating roller; the backing roller and the base material abut against each other, the backing roller can convey the base material in the autorotation process, in the conveying process of the base material, the coating in the coating area is transferred to the surface of the base material, and a slurry layer is formed on the surface of the base material; the comma knife is arranged on one side of the coating roller, a knife face is arranged on the side, close to the coating roller, of the comma knife, a gap is reserved between the knife face and the coating roller, and protruding parts protruding towards the direction of the coating roller are arranged at the two ends of the knife face. And through the arrangement of the convex parts, a series of technical problems caused by peak formation during coating are solved.

Description

Technical Field

[0001] This utility model relates to the field of coating, specifically to a transfer coating mechanism and a transfer coating device. Background Technology

[0002] In existing transfer coating methods, an interface is formed on the coating roller at the coating edge. After being transferred to the foil, the slurry forms another interface on the foil. Due to the surface tension of the foil, the slurry forms a peak on the paste surface, which cannot be as smooth as the rest of the paste surface (see Appendix). Figure 4 The thickness at this location is higher than that at other locations. The main hidden dangers of this problem are: 1) Because there is a peak on both sides, the thickness at the peak is greater than the normal coating thickness. During rolling, the compaction density at this location is too high and the tape is prone to breakage; 2) In the stacking process, the cumulative effect of the excessive thickness at this location will seriously affect the thickness and flatness of the battery.

[0003] Currently, there is no good method to control the spikes caused by the edge effect of the slurry; the only way to alleviate the problem is to reduce the slurry viscosity and increase its leveling properties. How to solve the series of technical problems caused by the spikes resulting from the edge effect of the slurry remains a pressing technical issue that needs to be addressed. Utility Model Content

[0004] To overcome the above-mentioned shortcomings, the purpose of this utility model is to provide a transfer coating mechanism that can solve a series of technical problems caused by the sharp peaks generated by the edge effect of the slurry.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: a transfer coating mechanism, comprising:

[0006] A coating roller has a slurry trough on one side. During the rotation of the coating roller, the slurry in the slurry trough is coated on the surface of the coating roller to form a coating area on the surface of the coating roller.

[0007] A back roller, a substrate, and the back roller abut against each other. The back roller can transport the substrate during its rotation. During the transport process, the coating in the coating area is transferred to the surface of the substrate, forming a slurry layer on the surface of the substrate.

[0008] A comma-shaped blade is disposed on one side of the coating roller. The comma-shaped blade has a blade surface on the side close to the coating roller, and there is a gap between the blade surface and the coating roller. Protrusions protruding towards the coating roller are provided at both ends of the blade surface.

[0009] By creating protrusions, a slurry layer that is thicker in the middle and thinner at both ends is formed on the surface of the substrate. Since the thickness at both ends of the slurry layer is thinner than the normal coating thickness, even if peaks form at the ends due to edge effects, the height of these peaks will be lower than the normal coating thickness in the middle of the slurry layer. Because the thickness of the peaks will not exceed the normal coating thickness, excessive compaction density at that location during rolling will not lead to tape breakage. Furthermore, this location will not be too thick during the stacking process, thus not affecting the battery thickness and flatness. Therefore, this application solves a series of technical problems caused by the formation of peaks during coating by improving the structure of the comma-shaped blade.

[0010] Furthermore, the thickness of the protrusion at the end of the comma blade is greater than the thickness of the protrusion near the middle of the comma blade. This results in a slurry layer that is thicker in the middle and gradually thins towards both ends, effectively controlling the distribution of the slurry on the substrate and ensuring the uniformity and consistency of the coating.

[0011] Furthermore, the main view projection of the protrusion is a triangle, the protrusion includes an inclined surface, the inclined surface and the blade surface form an angle, the angle being greater than 0°.

[0012] Furthermore, the included angle range is 0 < a ≤ 5°. By controlling the included angle between 0 and 5°, the length of the protrusion is relatively long, which can cover the area where the edge effect occurs, and no more spikes will be generated in the area between the two protrusions at both ends of the comma knife.

[0013] Furthermore, the main view projection of the protrusion is rectangular, and the height T of the protrusion protruding towards the coating roller is 0 < T ≤ 50 μm. By setting the rectangular protrusion, after transfer coating, the electrode edge has a gradient thinning effect. Although the electrode edge will also produce a peak due to the edge effect, the thickness of this peak is less than the thickness of the normal position of the electrode. The overall edge thickness is thinner, less than the thickness of the normal coating surface by 5~20 μm. Such an electrode will not have over-pressure problems during subsequent rolling processes, the electrode extension is basically uniform, and winding is good. This effectively solves the problem of peak thickness at the electrode edge and the problems of over-pressure, electrode deformation, wrinkling, and poor winding during subsequent rolling processes.

[0014] Furthermore, the height T of the protrusion protruding towards the coating roller is 20 < T ≤ 50 μm. This ensures that even if a 5-20 μm peak is formed at the edge of the substrate 5, the height of the peak will be lower than the thickness of the slurry layer.

[0015] Furthermore, the main view projection of the protrusion is a right trapezoid, and the thickness of the protrusion at the end of the comma blade is greater than the thickness of the protrusion near the middle of the comma blade.

[0016] Furthermore, the main view projection of the protrusion is stepped, with the number of steps n≥2, and the thickness of the protrusion at the end of the comma blade is greater than the thickness of the protrusion near the middle of the comma blade.

[0017] Furthermore, the protrusion and the blade surface are integrally connected. This improves the strength of the connection between the protrusion and the comma blade, and also avoids the need for connecting parts between the protrusion and the blade surface, making the structure of the comma blade simpler.

[0018] Furthermore, the comma blade is connected to a drive mechanism, which can drive the comma blade to move closer to or further away from the coating roller, thereby controlling the coating thickness.

[0019] A transfer coating apparatus, comprising a transfer coating mechanism as described above.

[0020] The beneficial effects of this utility model are:

[0021] 1) By setting the protrusions, a slurry layer with a thicker middle and thinner ends is formed on the surface of the substrate. Since the thickness of the slurry layer at both ends is thinner than the normal coating thickness, even if peaks are formed at both ends due to edge effects, the height of the peaks will be lower than the normal coating thickness in the middle of the slurry layer. Because the thickness of the peaks will not exceed the normal coating thickness, it will not cause excessive compaction density at that location during rolling, which could easily lead to tape breakage; and in the stacking process, this location will not be too thick, thus not affecting the thickness and flatness of the battery. Therefore, this application solves a series of technical problems caused by the formation of peaks during coating by improving the structure of the comma blade.

[0022] 2) By controlling the included angle between 0 and 5°, the length of the protrusion is relatively long, which can cover the area where the edge effect is generated, and no spike will be generated in the area between the two protrusions at both ends of the comma knife.

[0023] 3) By setting the rectangular protrusions, after transfer coating, the edge of the electrode sheet has a gradient thinning. Although the edge of the electrode sheet will also produce a peak due to the edge effect, the thickness of this peak is less than the thickness of the normal position of the electrode sheet. The overall thickness of the edge becomes thinner, which is 5~20μm less than the thickness of the normal paste surface. Such an electrode sheet will not have the problem of overpressure in the subsequent rolling process. The electrode sheet extension is basically the same and the winding is good. It effectively solves the problem of the peak thickness of the electrode sheet edge and the problems of overpressure, electrode sheet deformation, wrinkling and poor winding in the subsequent rolling process. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a transfer coating mechanism according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a comma knife in the prior art according to an embodiment of the present utility model;

[0028] Figure 3 This is a schematic diagram of an ideal slurry layer according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the actual state of the slurry layer according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the triangular protrusion in one embodiment of the present invention;

[0031] Figure 6 for Figure 5 A magnified view of a portion of the image;

[0032] Figure 7 A schematic diagram of a slurry layer prepared using a comma-shaped cutter with triangular protrusions;

[0033] Figure 8 This is a schematic diagram of a rectangular protrusion according to an embodiment of the present invention;

[0034] Figure 9 for Figure 8 A magnified view of a portion of the image;

[0035] Figure 10 A schematic diagram of a slurry layer prepared using a comma-shaped cutter with rectangular protrusions;

[0036] Figure 11 This is a schematic diagram of a stepped protrusion according to an embodiment of the present invention;

[0037] Figure 12 This is a schematic diagram of a right-angled trapezoidal protrusion according to an embodiment of the present invention.

[0038] In the diagram: 1. Comma blade; 11. Blade face; 2. Coating roller; 3. Slurry tank; 4. Coating area; 5. Substrate; 6. Slurry layer; 61. Peak; 7. Back roller; 8. Protrusion; 81. Inclined surface; 82. Angle; 9. Gap. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0040] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0041] See appendix Figure 1 As shown, the transfer coating mechanism in this embodiment includes a back roller 7, a substrate 5, and a back roller 7 in contact with each other. The back roller 7 is connected to a drive mechanism, which drives the back roller 7 to rotate. During the rotation of the back roller 7, the substrate 5 is conveyed. The coating device also includes a coating roller 2, which is located on the left side of the back roller 7. A slurry tank 3 is located on the left side of the coating roller 2. The position of the coating roller 2 is fixed, and the coating roller 2 is connected to the drive mechanism. The coating roller 2 can rotate under the drive of the drive mechanism. During the rotation of the coating roller 2, the slurry in the slurry tank 3 is coated onto the surface of the coating roller 2, forming a coating area 4 on the surface of the coating roller 2. During the clockwise rotation of the coating roller 2, the slurry in the coating area 4 is transferred to the substrate 5, forming a slurry layer 61 on the surface of the substrate 5.

[0042] A comma-shaped blade 1 is positioned above the coating roller 2. The comma-shaped blade 1 is connected to a drive mechanism, which can drive the comma-shaped blade 1 to move closer to or away from the coating roller 2. The comma-shaped blade 1 can evenly distribute the slurry in the coating area 4 and then transfer it onto the substrate 5. By setting the comma-shaped blade 1, the slurry distribution in the coating area 4 is ensured to be uniform, thereby ensuring that the slurry layer 6 on the substrate 5 is evenly distributed.

[0043] In the prior art, see Appendix Figure 2 As shown, the blade 11 of the conventional comma-shaped blade 1 is a straight line, parallel to the surface of the coating roller 2, to ensure that the slurry is evenly coated on the substrate 5. Ideally, see Appendix Figure 3 As shown, the slurry is evenly coated on the substrate 5, forming a smooth slurry layer 6. However, due to the edge effect of the coating, as shown in the attached image... Figure 4As shown, the coating material uniformly coated on the substrate 5 forms a slurry layer 6 with spikes 61 on both sides. Because the thickness of the spikes 61 is greater than the normal coating thickness, the excessive compaction density at this location during rolling can easily lead to strip breakage; furthermore, in the stacking process, the thickness at this location, being too thick, can cause a cumulative effect that severely affects the battery thickness and flatness; and the uneven thickness at this location can lead to lithium plating, posing a safety risk. This application addresses a series of technical problems caused by the formation of spikes 61 during coating by improving the structure of the comma blade 1.

[0044] See appendix Figure 5 and attached Figure 6 As shown, the comma-shaped blade 1 of this application has a straight center section on its blade face 11. Protrusions 8 are provided at both ends of the blade face 11, protruding towards the coating roller 2. These protrusions 8 create a gap 9 between the comma-shaped blade 1 and the coating roller 2, wider in the middle and narrower at both ends. The width of this gap is the thickness of the slurry in the coating area 4. Therefore, a coating layer thicker in the middle and thinner at both ends is formed on the surface of the coating roller 2. When the coating is transferred to the substrate 5, see the attached diagram. Figure 7 As shown, a slurry layer 6 with a thicker middle and thinner ends is also formed on the surface of the substrate 5. The "thicker middle" here refers to the thickness of the coating at both ends of the substrate 5. The thickness of the slurry layer 6 in the middle of the substrate 5 is the typical thickness of the slurry layer 6 in the conventional coating process, while the "thinner ends" simply means that the thickness of the slurry layer 6 at both ends is thinner than the thickness of the coating in the middle.

[0045] Because the thickness at both ends of the slurry layer 6 is thinner than the normal coating thickness, even if peaks 61 are formed at both ends due to the edge effect, the height of the peaks 61 will be lower than the normal coating thickness in the middle of the slurry layer 6. Since the thickness at the peaks 61 will not be greater than the normal coating thickness, it will not cause excessive compaction density at this location during rolling, which could easily lead to strip breakage. Furthermore, this location will not be too thick during the stacking process, thus not affecting the battery thickness and flatness. Therefore, this application solves a series of technical problems caused by the formation of peaks 61 during coating by improving the structure of the comma blade 1.

[0046] In some embodiments, the protrusion 8 and the blade 11 are integrally connected, which improves the firmness of the connection between the protrusion and the comma blade, and also avoids the need to set a connecting part between the protrusion 8 and the blade 11, making the structure of the comma blade 1 simpler.

[0047] In some embodiments, the protrusion 8 is formed by bending the blade surfaces 11 at both ends toward the coating roller 2. The main view projection of the protrusion 8 is triangular. The protrusion 8 includes an inclined surface 81, and a gap 9 is left between the inclined surface 81 and the coating roller 2 to ensure that a slurry layer 6 can be formed on the substrate 5. The inclined surface 81 and the blade surface 11 of the comma blade 1 form an angle 82, and the angle 82 is in the range of 0 < a ≤ 5°, that is, the two ends of the comma blade 1 are inclined at 0~5° toward the coating roller 2 respectively.

[0048] If the included angle 82 is too large, in order to ensure a gap between the protrusion 8 and the coating roller 2, the length of the protrusion must be relatively short, which cannot completely cover the area where the edge effect occurs. This may result in another spike in the area between the two protrusions, failing to effectively solve the spike 61 problem. Verification shows that when the included angle is controlled between 0 and 5°, the length of the protrusion 8 is longer enough to cover the area where the edge effect occurs, and spike 61 will not occur in the area between the two protrusions 8 at both ends of the comma-shaped blade 1. The length of the protrusion refers only to its length along the direction extending from the blade surface 11.

[0049] After the conventional comma blade 1 completes the transfer coating, due to the surface tension of the foil, the slurry will form an edge effect at the junction of the foil and the paste surface, resulting in a paste surface peak 61 in the slurry layer 6. The thickness at this position is generally 5 to 20 micrometers higher than the normal position thickness (single side). In the subsequent electrode rolling process, because the thickness at this position is too thick, it will cause the electrode at this position to be over-pressed, and the foil will stretch more than the stretch at other positions, resulting in uneven stretching of the electrode as a whole, causing the electrode to wrinkle, unable to be rolled normally, or even breakage and other serious defects.

[0050] See appendix Figure 7 As shown, due to the inclined surface 81 of the comma blade 1 of this utility model, after transfer coating, the edge of the electrode has a gradual thinning. This prevents the presence of sharp peaks 61 on the edge of the slurry layer 6, and at the same time, the edge is appropriately thinned, with a thickness of about 5~20μm less than the thickness of the normal slurry surface. Such an electrode will not have the problem of overpressure in the subsequent rolling process, and the electrode extension is basically the same, resulting in good winding. It effectively solves the problem of the thickness of the sharp peaks 61 on the edge of the electrode, as well as the problems of overpressure, electrode deformation, wrinkling, and poor winding in the subsequent rolling process.

[0051] In other embodiments, see Appendix Figure 8-10 As shown, the main view projection of the protrusion 8 is rectangular, and the height T protruding towards the coating roller 2 is 0 < T ≤ 50 μm. Through the setting of the rectangular protrusion 8, after transfer coating, the electrode edge has a gradient thinning effect. Although the electrode edge will also produce a peak 61 due to the edge effect, the thickness of this peak 61 is less than the thickness of the electrode at its normal position. The overall edge thickness is thinner, less than the thickness of the normal coating surface by 5~20 μm. Such an electrode will not have over-pressure problems during subsequent rolling processes, and the electrode extension is basically uniform, resulting in good winding. This effectively solves the problem of the thickness of the peak 61 at the electrode edge, as well as the problems of over-pressure, electrode deformation, wrinkling, and poor winding during subsequent rolling processes.

[0052] Preferably, the height T of the protrusion 8 protruding towards the coating roller 2 is 20 < T ≤ 50 μm, so as to ensure that even if a 5~20 μm peak 61 is formed at the edge of the substrate 5, the height of the peak 61 will be lower than the thickness of the slurry layer 6.

[0053] In some embodiments, see Appendix Figure 11 As shown, the main view projection of the protrusion 8 is a right trapezoid, and the hypotenuse of the trapezoid causes the slurry layer 61 to gradually thin. See Appendix Figure 12 As shown, the main view projection of the protrusion 8 can also be stepped, with the number of steps n≥2. The specific number of steps depends on the actual needs and is not limited in this application.

[0054] By setting the protrusion 8, the thickness of the film layer at the edge of the slurry layer 6 is reduced during the coating process on the substrate 5, thus solving the problem of peaks 61 caused by edge effects. The specific shape of the protrusion 8 can be set to achieve the desired technical effect; for example, it can be triangular, rectangular, right-angled trapezoidal, or stepped in the main view projection. This application does not list them all.

[0055] By setting protrusions 8 at the blade surfaces 11 at both ends of the comma blade 1, the edge of the electrode will gradually or gradient thin after the transfer coating is completed. This is very beneficial for the subsequent turnover and processing of the electrode after the transfer coating. Compared with conventional processes, this patent is of great significance for controlling the edge thickness of the transfer coating in lithium-ion batteries.

[0056] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0057] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They cannot be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A transfer coating mechanism characterized by, The application relates to a transfer coating device, which comprises the following parts: a coating roller (2) provided with a slurry groove (3) on one side, in the process of self-rotation of the coating roller (2), slurry in the slurry groove (3) is coated on the surface of the coating roller (2) to form a coating area (4); a back roller (7) capable of conveying a base material (5) in the process of self-rotation, in the process of conveying, the coating of the coating area (4) is transferred to the surface of the base material (5) to form a slurry layer (6); a comma knife (1) provided on one side of the coating roller (2), the comma knife (1) is provided with a knife face (11) on the side close to the coating roller (2), a gap is left between the knife face (11) and the coating roller (2), and convex parts (8) protruding towards the coating roller (2) are arranged at both ends of the knife face (11).

2. The transfer coating mechanism according to claim 1, wherein The thickness of the convex parts (8) at the ends of the comma knife (1) is greater than the thickness of the convex parts (8) close to the middle part of the comma knife (1).

3. The transfer coating mechanism according to claim 2, wherein The main projection of the convex parts (8) is a triangle, the convex parts (8) comprise an inclined face (81), the inclined face (81) and the knife face (11) form an included angle (82), and the included angle (82) is greater than 0 DEG.

4. The transfer coating mechanism according to claim 3, wherein The included angle (82) ranges from 0 to 5 DEG.

5. The transfer coating mechanism of claim 1, wherein, The main projection of the convex parts (8) is a rectangle, the height T of the convex parts (8) protruding towards the coating roller (2) is 0 < T <= 50 mu m.

6. The transfer coating mechanism according to claim 1, wherein The height T of the convex parts (8) protruding towards the coating roller (2) is 20 < T <= 50 mu m.

7. The transfer coating mechanism according to claim 2, wherein The main projection of the convex parts (8) is a right trapezoid or a ladder shape, and the number n of steps is greater than or equal to 2.

8. The transfer coating mechanism of claim 1, wherein, The convex parts (8) and the knife face (11) are integrally connected.

9. The transfer coating mechanism of claim 1, wherein, The comma knife (1) is connected with a driving mechanism, and the driving mechanism can drive the comma knife (1) to move close to or away from the coating roller (2).

10. A transfer coating device comprising the transfer coating mechanism according to any one of claims 1-9.

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